Martin Luther King Jr. was leading his “Poor People’s Campaign” when he was assassinated in Memphis, Tenn., on April 4, 1968.

King’s campaign, and its call for economic fairness, was what brought him to the city to march with striking public-works employees.

The day before he was killed, King addressed death threats, saying he “might not get” to the promised land of justice with others who sought it, but he knew “we, as a people,” would.

Among those who have embraced the spirit of that interrupted anti-poverty campaign is Tavis Smiley, 47, host of a weeknight talk show on PBS and the weekly public-radio program “The Tavis Smiley Show.”

“I regard Dr. King as the greatest American,” says Smiley by phone from Los Angeles. “At the end of his life, his work was about the poor, about lifting the least among us.”

Also inspired was Cornel West, 58, a familiar civil-rights activist, author (“Race Matters”) and philosophy professor at Princeton University. Last November, West spoke to Occupy Seattle protesters at Seattle Central Community College.

Both men, longtime friends and stars of “Smiley & West,” another public-radio program heard 4 p.m. Sundays on KUOW 94.9 FM, are appearing Tuesday at the Neptune Theatre as part of an ongoing effort to keep the subject of rising poverty rates high on the national agenda.

The pair’s three-week tour includes guest spots on television news shows and “The Colbert Report.”

Ticket holders will receive a copy of Smiley and West’s recently published book, “The Rich and the Rest of Us: A Poverty Manifesto.”

A blunt yet graceful assessment of how this country’s middle class is vanishing, and why national leaders aren’t seriously focused on the crisis, “Manifesto” has the same tone of empathy and personal inquiry (both writers grew up in poverty) that is heard on “Smiley & West.”

Since the program’s debut in 2010, “Smiley & West” has evolved from a series of penetrating discussions and interviews (West’s conversation with Stephen Sondheim is particularly memorable) to passionate-but-civil advocacy.

Street-level testimony on the show from people recently made jobless and homeless all over the U.S. has been sad and shocking.

Other topical programs do the same, but the echo of King’s lessons about love as a tool for social transformation has been prominent — and haunting — on “Smiley & West.”

“When we met 25 years ago,” says Smiley of himself and West, “we made a commitment to remain faithful to those things we believe in. What we strongly believe is that our destiny as a democracy is inextricably linked to how seriously we take King’s legacy of justice for all, service to others, and the love that liberates people.

“When you combine the perennially poor with the new poor and near-poor, you’re talking 150 million Americans,” says Smiley. “That’s half this nation. Poverty threatens democracy and national security.

“The next president, if he really understands the situation, will make his first official act the establishment of a White House conference eradicating poverty. It can be done.”